[PATCH 2/2] Revert "arm: mvebu: x240: Use i2c-gpio instead of built in controller"

[Stefan Roese]

On 10/3/23 05:57, Chris Packham wrote:
> This reverts commit 5c1c6b7306f2b4c0fd50c7cb5d757e245b93606e. The reason
> for switching to i2c-gpio was due to an issue we were seeing in the
> Linux kernel where the CPU would lock up on certain adverse I2C bus
> conditions. We were never able to reproduce the lockup in U-Boot but
> assumed that was probably just luck.
> 
> Since then we have discovered that the lock up was due to the I2C
> transaction offload engine in the I2C controller not coping with the
> adverse bus conditions (basically it thinks there's another master and
> waits for a STOP condition that never comes). U-Boot doesn't use the I2C
> offload feature so is not susceptible to the lockup.
> 
> We can therefore safely return to using the built-in I2C controller.
> 
> Signed-off-by: Chris Packham <judge.packham at gmail.com>

Reviewed-by: Stefan Roese <sr at denx.de>

Thanks,
Stefan

> ---
> 
>   arch/arm/dts/ac5-98dx35xx-atl-x240.dts | 30 ++++++--------------------
>   configs/x240_defconfig                 |  1 -
>   2 files changed, 7 insertions(+), 24 deletions(-)
> 
> diff --git a/arch/arm/dts/ac5-98dx35xx-atl-x240.dts b/arch/arm/dts/ac5-98dx35xx-atl-x240.dts
> index c19b25925ba2..820ec18b4355 100644
> --- a/arch/arm/dts/ac5-98dx35xx-atl-x240.dts
> +++ b/arch/arm/dts/ac5-98dx35xx-atl-x240.dts
> @@ -16,7 +16,7 @@
>   		gpio0 = &gpio0;
>   		gpio1 = &gpio1;
>   		spi0 = &spi0;
> -		i2c0 = &i2cgpio;
> +		i2c0 = &i2c0;
>   		usb0 = &usb0;
>   		pinctrl0 = &pinctrl0;
>   	};
> @@ -40,19 +40,6 @@
>   			default-state = "on";
>   		};
>   	};
> -
> -	i2cgpio: i2c-gpio-0 {
> -			compatible = "i2c-gpio";
> -			#address-cells = <1>;
> -			#size-cells = <0>;
> -
> -			pinctrl-names = "default";
> -			pinctrl-0 =  <&i2c0_gpio>;
> -			scl-gpios = <&gpio0 26 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
> -			sda-gpios = <&gpio0 27 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
> -			i2c-gpio,delay-us = <2>;
> -			status = "okay";
> -		 };
>   };
>   
>   &nand {
> @@ -83,7 +70,9 @@
>   	status = "okay";
>   };
>   
> -&i2cgpio {
> +&i2c0 {
> +	status = "okay";
> +
>   	mux at 71 {
>   		#address-cells = <1>;
>   		#size-cells = <0>;
> @@ -188,8 +177,8 @@
>   	 * LED_OE_N              [23]
>   	 * USB_PWR_FLT_N         [24]
>   	 * SFP_INT_N             [25]
> -	 * I2C0_SCL              [26] (GPIO)
> -	 * I2C0_SDA              [27] (GPIO)
> +	 * I2C0_SCL              [26]
> +	 * I2C0_SDA              [27]
>   	 * USB_EN                [28]
>   	 * MONITOR_INT_N         [29]
>   	 * XM1_MDC               [30]
> @@ -212,7 +201,7 @@
>   	/*	     0    1    2    3    4    5    6    7    8    9 */
>   	pin-func = < 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff
>   		     0xff 0xff 1    1    1    1    0xff 0xff 0    0
> -		     0    0    0    0    0    0    0xff 0xff 0    0
> +		     0    0    0    0    0    0    1    1    0    0
>   		     1    1    1    1    0    0    0    0    0    0
>   		     0    0    0    1    1    1    >;
>   
> @@ -220,9 +209,4 @@
>   		marvell,pins = <0 1 2 3 4 5 6 7 8 9 10 11 16 17>;
>   		marvell,function = <2>;
>   	};
> -
> -	i2c0_gpio: i2c0-gpio-pins {
> -		marvell,pins = <26 27>;
> -		marvell,function = <0>;
> -	};
>   };
> diff --git a/configs/x240_defconfig b/configs/x240_defconfig
> index 0d5a19df25aa..4b1a761a9086 100644
> --- a/configs/x240_defconfig
> +++ b/configs/x240_defconfig
> @@ -42,7 +42,6 @@ CONFIG_CLK_MVEBU=y
>   CONFIG_GPIO_HOG=y
>   CONFIG_DM_PCA953X=y
>   CONFIG_DM_I2C=y
> -CONFIG_DM_I2C_GPIO=y
>   CONFIG_SYS_I2C_MVTWSI=y
>   CONFIG_I2C_MUX=y
>   CONFIG_I2C_MUX_PCA954x=y

Viele Grüße,
Stefan Roese

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